Sugar-cane mill



F. J. DE BRUIN.

SUGAR CANE MILL.

APPLICATION FILED FEB. 4. 1920.

1,372,006. Patented Mar. 22, 1921.

2 SHEETS-SHEET liMamey F. J. DE BRUIN.

SUGAR CANE MILL.

APPLICATION FILED FEB. 4, 1920;

Patented Mar. 22,1921.

2 SHEETS-SHEET 2.

VVENTOR WOZQQBQ'aYIZ A/lorney tie rod bein UNITED. STATES PATENT OFFICE.

seem-own. MILL.

Specification of Letters Patent.

Patented Mar. 22, 1921.

Application filed February 4, 1920. Serial No. 356,271.

To all whom it may concern:

Be it known that I, FREDERIK JACOB DE BRUIN, a subject of the Queen ofthe Netherlands, residing at Rotterdam, Netherlands, have inventedcertain new and useful Improvements in Sugar-Cane Mills, of which thefollowing is a specification.

This invention relates to improvements in sugar cane mills.

In the usual mills with three rollers, in which the vertical directionof the hydraulic pressure acting on the top roller cannot be varied,great fluctuations are caused in the pressure by irregularities in thecharging of the mill.

Various means have already been proposed and some of them tried inpractice for the purpose of removing these great fluctuations inpressure.

The majority of these cases is based on the following consideration,viz., owing to the unavoidable irregularities in the charging of suchmills with sugar cane, the top roller must be adapted so that it mayselect its own position in relation to the two side rollers, with theresult that the size of'the admission and outlet gaps is automaticallyadjusted in accordance with the thickness of the layer of sugar canepresent at any particular moment in either of these gaps.

This consideration resulted in the employment of the so-called floatingtop rollers, two forms of which are in general use.

According to one of these forms the two mill housings each consist of alower portion comprising the trunnions of the side rollers mountedtherein, and an upper portion, movable in relation to the lower portionand connected by a tie rod, to a pivot located vertically beneath thetop roller, the attached to the upper portion and traverslng the lowerhousing portion.

In the other form of construction of these existing mills the bushes ofthe bearings of the top roller, which, accurately fitting in the slotsin the top of the housings, are ordinarily only capable of a verticalmove ment, are narrower in their width to such an extent that the toproller is enabled to move also in a lateral direction to an extentsuflicient to allow of an adaption to the fluctuations in the supply ofsugar cane to the mill. In order to diminish the friction between thebearing brasses and the hy-' draulic plungers bearing thereon, rollerbearings were provided. By means of these top rollers, which were thuscapable of movement in every direction, it was actually possible toexert an almost absolutely uniform pressure on the sugar cane. Thereexisted however the great disadvantage that the pressure in the rearopening of the mill was much too slight to insure an 'efiicient totalsqueezing and crushing effect.

This must be attributed to the fact that the pressure exerted by thehydraulic means on the top roller, owing to the unalterable verticaldirection of the same, was necessarily distributed equally over the twoside rollers.

At any rate this applied to mills when brought to a standstill while infull running. During crushing, the front pressure, owing to the actionof the circumferential force residing in the top roller, which is drivenby the steam engine, was even considerably higher than the rearpressure.

As the front pressure of the mill cannot be increased beyond a certainmaximum without causing a slipping of the rollers over the sugar cane,the rear pressure, when using the well known top rollers with pendulummotion, became so slight that an efficient squeezing effect Was quiteout of the question.

The object of thisinvention is to remove sists in allowing a floatingtop roller of this disadvantage, and substantially con- I knownconstruction to act by means of the hydraulic pressure in such adirection on the lower rollers that both in the front opening and in therear opening of the mill a pressure will always be exerted, which-ismost suitable for insuring an eflicient squeezing and crushing of thesugarcane.

Several forms of the invention are illustrated by way of example in theaccompanying drawings in which:

Figure 1 shows one form in end elevation, and Fig. 2 a.half sectionalfront elevation respectively, whereas Figs. 3 and 4, 5 and 6 and 7 and8, are similar views of other forms of the improved mill, constructed inaccordance with the invention.

In the form of mill shown in Figs. 1 and 2, the lower portions of themill housings 1 contain only the two' side rollers 2 and 3, which arefree to rotate but are otherwise fixed with respect to theirbearings,.whereas a floating top roller 4, belonging to the well knowntie. rod type, is mounted by means of pins 5 and of pendulums 6 inbearing blocks 7, which are fixed parts of the bed plate 8 of the mill.

The under parts of the pendulums 6 as well as the bearing blocks 7possess a number of holes into which the pins 5, one at each side of themill, can be set, so that the resultant of the two forces transmitted bythe top roller to the side rollers are adjusted in a correspondinglyoblique direction by which means the desired regulation ofthe front andrear pressure is obtained.

The adjusted relationship between this front pressure and rearpressure'in each particular case can no longer beinfiuenced even bythemost negligent charging of the mill with sugar cane, whereas thetotal pressure can be regulated by varying the pressure of theaccumulator.

Another form of the invention for solving this problem is shown in Figs.3 and 4 in which the mill housings are each divided into a lower section11, containing the two fixedly mounted side rollers 12 and 18, and anupper section or cap 14, containing a top roller movably mounted thereinand constructed on the roller bearing principle, the said movementtaking place along a circular path, the center of which coincides withthe axis of the top roller.

By placing these pivoting upper sections or caps of the housings in anoblique position, the desired regulation of the front and rear pressureis obtained. This can be done by lengthening one of the two bolts 16 and1 which connect the upper section or cap to the lower section of thehousings, and by simultaneously shortening the other of these two bolts.v

This intended oblique adjustment of the hydraulic means could also beeffected, as shown in Figs. 5 and 6, by moving the plungers 18 of thehydraulic rams over circular sliding tracks20 fixed to the housings 19.

In this form the top roller is movably mounted 0H1 roller bearingsarranged between the bearing bushes 21 and the cylinders 22 of thehydraulic rams.

Further, as shown in Figs. 7 and 8, the

y direction in which the hydraulic pressure acts, could be changed bypartially rotating or oscillating closed ring shaped yokes 24,

pivotally mounted between the lateral faces of the housings 23, two ofwhich yokes are always rigidly connected to one of the cylinders 22 ofthe hydraulic rams. In this form V of the invention the movably mountedtop roller is also a floating roller of the well known roller bearingtype.

In order to avoid a one-sided load on the trunnions of the mill rollersand roller bearings and a consequent heating of these trun In mills asshown in' F i s. 1 and 2, 5 and 6 and 7 and 8, this result is insured byproviding spherical surfaces after the type of the well known Sellerstransmission bearing blocks, whereas in the form shown in Figs. 3 and 4,where the hydraulic contrivance presses on the bearing brasses by meansof balls instead of rollers, cylindrical intermediate members 26 areprovided between the ball bearings 27 and the hydraulic pistons 28.

,These intermediate members, on occurrence of a one-sided raising orlowering of the top roller, will move in an axial direction withreference to the bearing brasses,

thus enabling the balls to roll in the longitudinal direction of themill rollers.

The reduction of friction between the bearing brasses and the hydraulicrams, see Figs. 3 to 8, may also be effected by other means than thewell known roller bearings or ball bearings, for instance by introducinglubricating oil under high pressure between fiat and slightly concavesliding faces.

This invention is not restricted to the above described forms ofconstruction, on the contrary it applies to all three-rollermills withmovably mounted, so-called floating top rollers, in which the directionof the resultant of the forces, transmitted by the top roller to boththe side rollers, is not vertical and can be chosen arbitrarily withincertain defined limits.

I claim:

1. In a three roller sugar cane mill, two housing parts fixedly boltedon the bed plate,

two side rollers not adjustably mounted quately powerful squeezing ofthe 'sugar gap of the mill, substancane in the rear tially as described.

2. In a three roller sugar cane mill, two housings divided in fixedunder and movable upper parts, two not adjustable side rollers, afloating top roller with hydraulic adjustment mechanism and means forregulating the amount of pressure on the side rollers, for the purposeof obtaining the desired relationship between the pressure at the inletand outletgaps of the mill, substantially as described.

3. In a three roller sugar cane mill, two housings divided in fixedunder and movable upper parts, two not adjustable side rollers, afloating top roller with hydraulic adjustment mechanism, means forregulating the amount of pressure on the side r011- ers, comp-risingpendulum extensions on the upper housing parts, pivots in the underparts thereof and means for changing the location of said pivots,substantially as and for the purpose described.

4. In a three roller sugar cane mill, two housings divided in fixedunder and movable upper parts, two not adjustable side rollers, afloating top roller with hydraulic adjustment mechanism, pendulumextensions on the upper housing parts, pivots in the pendulum underparts and means for changing the location of said pivots, said meansconsisting in a number of pivot holes in the pendulum and cooperatingpivot holes in a xed part of the mill.

5. In a three roller sugar cane mill, two

housings divided in fixed under and movable upper parts, two notadjustable side rollers, a noating top roller with hydraulic adjustmentmechanism, pendulum extensions on the upper housing parts,-pivots in thependulum under parts and means for changing the location of said pivots,comprising a number of pivot holes in the under parts of pendulums, bedlate extensions having an equal number of pivot holes spaced the samedistance apart as those in the pendulums, each pivot locatable inselected holes at each side of the mill, substantially as and for thepurpose described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses. 1

FREDERIK JACOB DE BRUIN.

\Vitnesses:

A. ROTSTEGE, J. KOOLMAN.

